Add -minimal mode to rustboot that skips emitting code that's broken or unneeded for rustc. Shrink rustc by 300kb. Back under 1mb.

2 files changed, 6 insertions, 0 deletions

diff --git a/src/boot/driver/main.ml b/src/boot/driver/main.ml
index 3c37a03250a..eacecc2d4f2 100644
--- a/src/boot/driver/main.ml
+++ b/src/boot/driver/main.ml
@@ -24,6 +24,7 @@ let (sess:Session.sess) =
     Session.sess_out = None;
     Session.sess_library_mode = false;
     Session.sess_alt_backend = false;
+    Session.sess_minimal = false;
     Session.sess_use_pexps = false;
     (* FIXME (issue #69): need something fancier here for unix
      * sub-flavours.
@@ -229,6 +230,10 @@ let argspecs =
     (flag (fun _ -> sess.Session.sess_use_pexps <- true)
        "-pexp"         "use pexp portion of AST");
 
+    (flag (fun _ -> sess.Session.sess_minimal <- true)
+       "-minimal"     ("reduce code size by disabling various features"
+                       ^ " (use at own risk)"));
+
     ("-zc", Arg.Int (fun i -> sess.Session.sess_fuzz_item_count <- i),
      "count of items to generate when fuzzing");
 
diff --git a/src/boot/driver/session.ml b/src/boot/driver/session.ml
index ae16c1395bc..8d7c331965c 100644
--- a/src/boot/driver/session.ml
+++ b/src/boot/driver/session.ml
@@ -13,6 +13,7 @@ type sess =
   mutable sess_out: filename option;
   mutable sess_library_mode: bool;
   mutable sess_alt_backend: bool;
+  mutable sess_minimal: bool;
   mutable sess_use_pexps: bool;
   mutable sess_targ: target;
   mutable sess_log_lex: bool;